Flexible implant resection arthroplasty of metacarpophalangeal joint in a rheumatoid hand is now a common medical procedure.
The postoperative care for the proximal interphalangeal joint depends on several factors, namely whether there was reconstruction of a stiff proximal interphalangeal joint, reconstruction of a swan-neck deformity, or reconstruction of a boutonniere deformity.
With regard to postoperative rehabilitation programs in flexible implant arthroplasty of the digits of a hand, finger slings of a dynamic brace have been used. These slings are placed on the proximal phalanges to assist metacarpophalangeal joint extension and guide alignment of the digits. The slings are adjusted to pull from radial sides to prevent ulnar deviation. Rubber bands are used with the slings to allow 70 degrees of flexion at the metacarpophalangeal joint, especially of the little finger.
If there is a tendency toward medial rotation (pronation) in the index or middle fingers, additional outrigger bars are applied to the brace to provide a rotation force at the metacarpophalangeal joints, according to the concept of a force couple, i.e., a force defined as two equal and opposite forces that act along parallel lines. This is obtained by applying a further loop to the digit that shows a tendency for pronation, and the combined pull of two slings on the one finger forms a coupling that produces a torque force in the direction of supination on the digit without interfering with flexion and extension movements.